Description The American shad or Atlantic shad, Alosa sapidissima, is a species of anadromous fish in family Clupeidae of order Clupeiformes. It is not closely related to the other North American shads. Rather, it seems to form a lineage that diverged from a common ancestor of the European taxa before these diversified (Faria et al. 2006).

The shad spends most of its life at sea, but swims up fresh rivers to spawn. The fish survive breeding and can return to the sea; they do not inhabit fresh water except to spawn. At sea, shad are schooling fish; thousands are often seen at the surface in spring, summer, and autumn. They are hard to find in the winter, as they tend to go deeper before spawning season; they have been pulled up in nets as deep as 65 fathoms (119 m).

Like other herrings, the American Shad is primarily a plankton feeder, but will eat small shrimp and fish eggs. Occasionally they eat small fish, but these are only a minor item in their general diet.